Resilient Cooperative Control Strategies For Seaport Microgrids Considering Cyber Attacks

With the increasing share of maritime transportation in global trade,seaports have become increasingly complex transport hubs.The rapid development of distributed power generation technology has provided the development ideas of seaport microgrids(SMGs)for shaping green seaports.Similar to land-based microgrids,SMGs can be upgraded from traditional power systems to smart grids with characteristics of cyber physical systems by applying distributed control methods based on communication technology.It not only ensures the reliable and stable operation of the seaport power system,but also promotes the automation and intelligence of the seaport.However,the distributed control structure is highly dependent on sensor technology and communication technology,making the power system vulnerable to potential cyber attacks,which may destabilize the power system,lead to large-scale power outage and then result in the seaport operation schedule delay.Therefore,it is a realistic topic to study the cyber attacks defense of SMGs.This paper aims to study the resilient cooperative control strategy for frequency,voltage synchronization and power sharing of SMGs under cyber attacks.The main work is as follows:Aiming at the problem of protecting sensors and actuators of SMGs from false data injection(FDI)attacks,a resilient control strategy based on an extended state observer(ESO)is proposed,which can eliminate the influence of attacks on the SMGs.First,virtual variables representing the reference value estimate of each distributed energy resources(DERs)are introduced as neighbor communication information and input to local controllers.Then an ESO is designed to estimate the FDI attacks on sensors and actuators.Based on the estimated values,a resilient controller is designed to compensate the impact of attacks.It is proved that the synchronization errors between the frequencies and the rated value are uniformly and ultimately bounded based on Lyapunov theory.Finally,the effectiveness of the proposed method is verified by MATLAB/simulink simulation in different scenarios.In order to prevent multiple cyber attacks on SMGs,the other distributed resilient control strategy based on virtual layer is proposed,which can resist the influence of multiple cyber attacks on the frequency and power of SMGs and then realize frequency recovery and power distribution.Firstly,the potential attack locations of SMGs are identified based on the characteristics of cyber attacks,and the time-varying bounded and state-dependent FDI attack models and denial of service(Do S)attack models are established respectively.Then the influence of several attacks on the frequency dynamics is analyzed theoretically.Then the other distributed resilient control strategy containing virtual control layer is designed.Lyapunov’s second method is used to prove the asymptotic stability of the frequency equilibrium state and the uniform ultimate boundedness of the synchronization error between frequencies and the rated value.Finally,the effectiveness of the proposed method is verified by several cases.